Celebrities Who Dare To Bare It All

The print campaign is expected to debut in October in magazines and posters, McGraw said. It will be launched first in Argentina, where Che Guevara was born, and then internationally. PETA approached the 24-year-old in recent months after finding out she was a vegetarian, McGraw said.

In the ad, Lydia Guevara wears camouflage pants, a red beret, and bandoliers of baby carrots while standing with one fist on her hip and the other outstretched.

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"It very much evokes the tag line of the ad, which is 'Join the vegetarian revolution,'" McGraw said. "It's an homage of sorts to her late grandfather."

Che Guevara was a Marxist leader who played a pivotal role in Fidel Castro's rise to power in Cuba. He was executed in Bolivia in 1967.

The ad is PETA's first campaign promoting vegetarianism in South America.

"We say the best way to save animals is not to eat them," McGraw said.

He said others who have promoted vegetarianism for PETA include Paul McCartney, Forest Whittaker and Alicia Silverstone.